Thanks to Jeff who notified me that the tilt sensor is available online today and also provided the following two general promotion codes which can be used for additional discounts!

10% Off total : 470000000024860

$10 off $50: 47000RRRRR0663R

***Update 6/2/2014 5:35pm ***

The link now shows the previous price of $30 and it’s unavailable for order now. 😦
I’ve purchased 2 and this afternoon and it’s still in process. I wonder what happen and will let you know if my order actually ships.